Listening to FM radio while driving is one the most pleasant tasks that almost everybody has experienced. We listen to our favour-ite music from our favourite station and at the same time get the updates of traffic and weather and etc. The FM broadcast band, by radio station, is not the same all over the world. In Europe and Africa (ITU region 1), it spans from 87.5 to 108.0 mega hertz (MHz), while in America (ITU region 2) it goes from 88.0 to 108.0 MHz; In Japan it uses 76.0 to 90 MHz. The OIRT band in Eastern Europe is from 65.8 to 74.0 MHz, although these coun-tries now primarily use the 87.5 to 108 MHz band, as in the case of Russia. Some other countries have already discontinued the OIRT band and have changed to the 87.5 to 108 MHz band.” In this study, a car antenna has been designed and simulated, and has proved ful-ly operational within all mentioned frequency bands. In this example, the performances of the antenna are assessed and described.

FM RADIO

ANTENNA SIMULATION

SIMULATION

Through this simulation, we should be able to get an approxi-mate idea about the emission and reception properties of the de-signed car antenna and in which way it is compatible with the mentioned multiple FM broadcast bands. The frequency plan used in this antenna simulation is fast sweep: the simulator tries to es-timate the curves of the antenna parameters which may be slightly decaled from the real values

BOUNDARY CONDITIONS

The placement of the antenna (in-side, outside the car, the relative position with regards to the BTS) should be taken into account in a post simulation or post study re-alization step. The port is applied to the Duroid 5880 small struc-ture whose outer face is treated as a PEC surface, and the anten-na’s stem is the RF signal carrie

RESULTS

The following figure shows the electric field radiation pattern of the car antenna at 90 MHz. The pattern is iden-tical for all Phi angles and show a revolution symmetry around the Z-axis. The ac-curacy of this 3D plot is af-fected by the Phi angle’s step defined since the study cre-ation. the smaller the step is the smoother the plot gets: here we have a step of 15°.

The return loss at the an-tenna’s port is around 15 dB from 60 MHz to 120 MHz which is acceptable and cov-ers the FM frequency bands mentioned in the introduc-tion.

This figure shows the radiation of the electric with the antenna’s stem at 90 MHz with a phase equal to π/2. This capture has been spot-ted by an animation or variation of the omega T phase at the maxi-mum of the electric field’s inten-sity.

ElectroMagneticWorks Inc. 8300 St-Patrick, Suite 300, H8N 2H1, Lasalle, Qc, Canada +1 (514) 634 9797 | www.emworks.com

ElectroMagnetic Design Made Easy

Powered By SolidWorks ©

© 2012 ElEctroMagnEticWorks, Inc. All Rights Reserved.